possible vent problem?

[TREERAT]

do I have a vent problem? on a two cavity mold the cav. close to the handle will not fill out the base sharp, other cav. does fine!
the mold is clean!
there is no defect in cavity!
I will not be adding tin, because other cavity fills perfect, sharp.
mold is beageld, so should vent well? also did this before beageling!
been playing with sprue plate ajustment to try to remeady!
lead is plenty hot as well as mold!

now I have a new theory! and want your opinion. when I cast I have always filled the farthest cavity first, which is the one that is working perfect, then the closer one. well my theory is that the far cavity has a head start cooling the sprue, which draws down as it cools, I think this pulls the plate down to tight to the mold blocks and decreases venting to the close cavity. does this sound plausable? next time I mold some bullets I will test my theory by filling the close (problem cavity) first! and see if it helps. but until then whats your opinion?

[docone31]

The mold is too cool.
Cast em at your preferred temp. Let them stay in the mold a little longer AFTER cutting the sprue. Keep moderating the temp untill they are what you are looking for.
It is not uncommon to get variances while casting.

[MT Gianni]

Loosen the sprue plate screw for additional venting in the rear cavity.

[runfiverun]

alternate pouring the holes helps too. if it is the back one all the time it might need more time to suck in the lead.

[TREERAT]

am I cutting the sprue at the right time? as it is solidifing it undergoes two mild color changes and pulls a little lead down in the middle of the sprue, then I cut. is this correct?

[docone31]

Yup, you cutting the sprue at the right time. The colour changes I call a "flash", then the center pulls in. That is when you cut it.
When the base pulls in, the mold is too cold.
More heat.
I rest my mold directly in the melt. When the lead falls off the mold, I pour. If the sprue stays liquid, I dump that casting(s), then wait a bit. I then cast. When the mold gets cold, or cooler, I let the castings stay in the cavities longer than I usually do.
You will develop a rythym. You will be able to heat soak the mold, and cast at a speed that stays right at the sweet spot. It doesn't matter which cavity you fill first. Just do the same things the same way. That develops consistancy.
Are you bottom pouring, or ladleing?
I bottom pour. I set my Lee 20lb pot on full tilt for the session. The heavier castings, I have to dump faster, and wait more often to keep them from staying liquid.

[captaint]

Tree - that's what I do. As soon as that puddle nearest me (I pour the farthest first) starts to shrink, it gets a little dimple in the center. Time to bop the sprue plate. I'm pretty new at this too, but this particular issue has not yet presented a problem. Had plenty of others tho.! Mike

[TREERAT]

I have always dipped my mold in the lead until the lead lill not stick, even though most mold makers frown on this. this way I can be making good bullets in about 10 - 15 drops, instead of screwing around dropping 50-75 bullets to get up to temp.

I bottom pour with a lee 10 lb pot. tryed laddleing still am not getting that figured out. do you try to be steady and laddel a stream? or hold mold and laddle together and toun up to fill mold? when I do the latter I get such a small sprue that I have to break my rythm an dig the sprue out of the plate, because it will not fall out!

[mikenbarb]

I had the exact same problem with a Saeco 115 and I had to loosen the spru plate to get it to fill out properly. Drove me nuts for 2 days and it was something as easy as that.

[Bret4207]

Many guys report a very light beveling of the top of the blocks with a fine stone solves sprue plate venting issues. We're talking like one stroke, no more.

[Calamity Jake]

What Brit said!!! GO REAL EASY

After appling the bevel lay the stone on mold top and pull from the cavity side out, this will remove any small burr caused by beveling, do the same for the faces

[TREERAT]

not quite shure where you want me to bevel? do you mean a very light chamfer around the edge of the base of the cavity. simular to chamfering a cartrige case mouth? but very lightly done. if so I have already done that.

[felix]

NO! Along the parting single edge of the mold. ... felix

[Capn Jack]

Are you using one of the small Lyman ladles? If so, are you making both pours from from a single "Dip"? I've found the Lyman ladle had to be nearly full when I poured, for a good boolit and if I tried two pours with the same ladle the second one wouldn't fill completely.:drinks:

OOPS! I missed the part about using a bottom pour pot

[TREERAT]

ok felix, and others -- still confused. mabye a small degree angle, slight V front to back where the block halves meet. so that I have a vent line front to back for the full length of the blocks, across both cavitys at the part line? this would make sense to me. is this what you are instructing me to try?

[felix]

Nothing to do with the cavities. It's across the top of the blocks. ... felix

[TREERAT]

still playing stupid, any posibility of a picture, you know what they say ( a picture is worth a thousand words)

P.S. where do look to find out how to post a picture?

[stocker]

The straight edges from front to back along the top need a small bevel to form a vent line when the mould is closed. There is no metal to remove where the cavities are is what Felix is getting at. Your stone will just slide over the half cavity. You don't try to remove any metal around the circumference of the cavity if that is what you are wondering.

[larrye44]

I'm new to casting also, what is beageld? treerat said "mold is beageld, so should vent well? also did this before beageling!" Thanks everyone. Larry

[TREERAT]

ok I beleive I finally understand, get alittle dense once in awhile.

beageling = placing some kind of shim between mold halves to create a larger size bullet.
usualy 3m flue tape is recomended. I used alluminium pop can shims, jb welded
in, then surfaced to get the gap to produce the bullet size I was needing.

[larrye44]

Thanks, TREERAT, for educating me on this. This is a great forum and I have already learned a lot. Hope to start casting soon. I already have my WW's melted down into ingots, and just waiting on my lube-a-sizer. Larry